Syringes of this type are described in the not published European patent application No. 84 100 711.5 and have the advantage that the needle attachement and the connection piece can be mounted easily even when the syringe is already filled and can afford a safe sealing of the syringe cylinder. For assembly it is sufficient to fit the coupling piece over the attachment placed on the cylinder nozzle and to push until it is securely lodged at the cylindrical nozzle. The syringe needle can be vulcanized in the connection neck protruding from the coupling piece or it can be glued therein with a heat-resistant glue. It also can be omitted at first, and just before the syringe is used, can be inserted in or fitted on the connection neck, for which purpose a luer cone can be provided onto which a needle guide sleeve carrying the needle can be fitted.
Generally, the luer cone can be recommended also in the case of differently attached needles because it makes it possible to fit over the syringe needle a cap receiving and protecting the same. If the syringe needle is attached on the connection neck only immediately before the use of the syringe, the exit of the needle attachment channel for the passage of the injectable substance can be closed by a so-called tip-cap, fitted on the luer cone and having a central projection reaching into the channel and sealing same.
In such syringes, the problem arises that in order to provide a good and reliable seal at the cylinder nozzle, the needle attachment is usually made of soft elastic material, which leads, on the other hand, to insufficient stiffness in the area of the connection neck to safeguard the mechanical stability of the needle.